I have setup an IPSec tunnel with the help of BGP for routing using a Netgate PFSense router, that works as desired.

Although I can RDP to a device on the other end of the tunnel when I'm plugged into the Netgate (Ethernet), I'm not able to do so when I'm connecting through my TPLink router, which has a route setup to the Netgate for the traffic meant for the tunnel.

I can ping the device, tracert shows it's routing properly, and the RDP attempt shows up on the other end, but the session doesn't establish, and the traffic is dropped.

Testing using "Test Port" was successful in PFSense.

I'm suspecting the issue is on the TPLink side, since when connected directly to the Netgate, RDP works fine.

Thoughts on this? What am I missing?

Thank you!